U.S. patent number 4,683,359 [Application Number 06/839,239] was granted by the patent office on 1987-07-28 for illuminated switch assembly with combined light and light shield.
This patent grant is currently assigned to Eaton Corporation. Invention is credited to Guy A. Wojtanek.
United States Patent |
4,683,359 |
Wojtanek |
July 28, 1987 |
Illuminated switch assembly with combined light and light
shield
Abstract
A switch assembly having a pushbutton actuator with graphics
backlit by an electroluminescent light source deposited upon a
mylar substrate. A separate indicator lamp is provided to be lit
when the function selected by the switch is activated. The
indicator light is visible through a small window in the
pushbutton. In order to prevent light from the indicator lamp from
impinging upon the graphics area, a portion of the mylar substrate
is opaquely coated to block the light transmission, while the
remainder of the mylar substrate is clear to insure proper
registration and prevent degradation of the electroluminescent
phosphor.
Inventors: |
Wojtanek; Guy A. (Franklin
Park, IL) |
Assignee: |
Eaton Corporation (Cleveland,
OH)
|
Family
ID: |
25279217 |
Appl.
No.: |
06/839,239 |
Filed: |
March 13, 1986 |
Current U.S.
Class: |
200/314;
200/310 |
Current CPC
Class: |
H01H
13/023 (20130101); H01H 2009/183 (20130101); H01H
2219/064 (20130101); H01H 2219/018 (20130101); H01H
2011/0081 (20130101) |
Current International
Class: |
H01H
13/02 (20060101); H01H 009/18 () |
Field of
Search: |
;200/312,314,317
;250/463.1,465.1,466.1 ;340/781,815.13 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Marcus; Stephan
Assistant Examiner: Luebke; Renee S.
Attorney, Agent or Firm: Rowe; D. A. Johnston; R. A.
Claims
I claim:
1. An illuminated switch assembly comprising:
a switch;
a switch actuator operative upon movement by an operator to
activate said switch with a display panel having a generally planar
display surface, the display surface having a first region of
graphic indicia adapted to be illuminated by a first source from
one side thereof away from the operator to display the function
controlled by the switch and a second region adapted to be
illuminated by a second source from said one side away from the
operator to indicate actuation of said switch, said actuator being
formed with a wall separating said first and second regions and
extending away from the display surface in a direction
substantially transverse thereto;
means defining a first support surface underlying said display
panel in close proximity to said display surface, said first
support surface being formed with an opening to allow said wall to
extend therethrough;
an electroluminescent panel mounted on said first support surface
underlying said first region but not said second region of said
display surface and operative as said first source of illumination,
said electroluminescent panel being formed as a sandwich comprising
plural layers with a layer having areas of electroluminescent
phosphor and electrical conductors thereon and disposed between
supporting transparant layers;
means defining a second support surface underlying said first
support surface;
a lamp mounted on said second support surface and disposed to
underly the opening of said first support surface and operative as
said second source of illumination; and,
shield means operative to prevent said lamp from illuminating said
first region and including a coating of opaque material on the
layer of said electroluminescent panel adjacent said first support
surface and adjacent said opening, said opaque material extending
along said layer a sufficient distance such that light from said
lamp cannot leak through the coated layer to said first region of
graphic indicia.
2. The assembly according to claim 1 wherein said shield means
further includes a flap formed from the coated layer and extending
into said opening.
Description
BACKGROUND OF THE INVENTION
This invention relates to an illuminated switch assembly of the
type having a display panel with a first area of graphic indicia
illuminated to display the function of the switch and a second area
illuminated to provide an indication that the function is
activated.
Pushbutton switches, such as the type found in automobiles, are
sometimes required to be backlit. This is for low light viewing of
the graphic indicia on the face of the pushbutton which illustrates
the function associated with the switch. In some instances, it may
also be required to indicate that the function has been activated
by means of an indicator light on this same surface. For aesthetic
reasons, it is undesirable to have the "on" indicator interferingly
backlit by the light source for the graphics, or vice versa. This
is especially true when the two light sources are different in
color. It is therefore a primary object of the present invention to
provide a cost effective means of stopping the transmission of
light between different adjacent backlit areas on the same
surface.
In the particular application with which the present invention is
concerned, the light source for back-lighting the graphics area is
an electroluminescent panel and the "on" indicator light source is
either a miniature incandescent lamp or a light emitting diode. In
this application, one possible solution to the light leakage
problem is to position the indicator light source within an opaque
shroud which is part of the button. With such an arrangement, the
indicator light source could either move with the button or be
stationary, having the button and shroud move relative to it.
However, both of these alternatives present problems. Thus, if the
indicator light source moves with the button, then the connection
to a power source for the light source becomes difficult, since it
may require additional parts, resulting in a higher cost. If, on
the other hand, the light source does not move with the button, it
must be mounted relatively close to the button. In many
applications, this may not be possible due to size constraints
placed upon the button and the graphics. In turn, this limits the
wall thickness of the shroud in the button because the extension of
the walls is dependent upon the thickness of the walls at the
parting line of the plastic button mold, since the walls must be
tapered to allow easy ejection from the mold. This limits how far
the walls of the shroud can extend down around the indicator light
source. In the particular application for which the present
invention was developed, the light source is mounted so far from
the button that the shroud walls cannot be made long enough to
envelope the light source or sufficiently baffle the light. Another
possible solution is to place a separate shroud around the
indicator light source. However, this is disadvantageous since it
would require an additional part, resulting in a higher cost. It is
therefore another object of the present invention to overcome the
aforementioned problems.
SUMMARY OF THE INVENTION
The foregoing, and additional, objects are attained in accordance
with the principles of this invention by providing an illuminated
switch assembly having a pushbutton with a graphics area backlit by
an electroluminescent panel mounted on a first support surface to
underly the graphics area. A separate indicator lamp is provided
and is lit when the function selected by the switch assembly is
activated. The indicator lamp illuminates a small window adjacent
the graphics area. A wall is provided separating the graphics area
from the window and extending toward the light sources. To prevent
light from the indicator lamp from impinging upon the graphics
area, a coating of opaque material is provided on the underside of
the electroluminescent panel. This coating extends a sufficient
distance away from the indicator lamp that light from the lamp
cannot leak through the electroluminscent panel.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing will be more readily apparent upon reading the
following description in conjunction with the drawings in which
like elements in different figures thereof have the same reference
character applied thereto and wherein:
FIG. 1 is a cross sectional view of a switch assembly in which the
present invention is incorporated;
FIG. 2 is a view similar to FIG. 1 showing the switch assembly with
the actuator button depressed;
FIG. 3 is a top plan view of an illustrative actuator button which
may be utilized in the construction shown in FIGS. 1 and 2;
FIG. 4 is a view taken substantially along the line 4--4 in FIG. 1;
and
FIG. 5 is an exploded perspective view of the actuator button and
the illumination sources of the assembly shown in FIGS. 1 and
2.
DETAILED DESCRIPTION
Referring now to the drawings, shown therein is a switch assembly,
designated generally by the reference numeral 10, contained within
a case 12. The assembly 10 includes a pushbutton actuator 14
mounted so as to cooperate with the actuator bar 16 to control the
position of the switch blade 18. The details of construction of the
switch, and its manner of operation, do not form a part of the
present invention.
Illustratively, the pushbutton 14 is a two-shot molded button, the
construction of which involves a molded clear acrylic insert 20
with a black ABS portion 22 molded around it. It is also includes
an integrally molded wall 24 and light pipe 26. The light pipe 26
forms a window 28 at its outer extremity on the surface of the
pushbutton 14.
As is clearly shown in FIG. 3, the portion of the pushbutton 14
which extends through the opening 30 in the case 12 forms a display
panel with a generally planar display surface 32. The display
surface 32 has a first region 34 of graphic indicia indicating the
function controlled by the switch assembly 10. Thus, the surface 32
is coated with an opaque material except in areas forming a graphic
pattern, so that when it is backlit the graphic pattern is
illuminated. For example, in an automobile, the switch assembly 10
may provide the function of activating the hazard light flashing
system and, accordingly, as illustrated in FIG. 3, the graphic
display region 34 has indicia to that effect. The display surface
32 also includes a second region for indicating when the function
associated with the switch assembly 10 is activated. This second
region includes the window 28. As will be described hereinafter,
the switch assembly 10 includes a first source for illuminating the
first region 34 to display the function and a second source for
illuminating the window 28 when the function is activated. These
sources are within the case 12 on the side of the pushbutton 14
away from the operator.
An electroluminescent panel 36 is provided to illuminate the
graphics region 34 and a lamp 38 is provided to illuminate the
window 28. To support the electroluminescent panel 36, there is
provided a first support surface 40 which underlies the pushbutton
14 in close proximity to the display surface 32. The support
surface 40 is formed with an opening 42 to allow the wall 24 to
extend therethrough when the pushbutton 14 is depressed, as shown
in FIG. 2. Thus, the opening 42 is aligned with the window 28. The
lamp 38 is mounted on a support surface 44, illustratively a
printed circuit board, in underlying relationship to the opening 42
so that when lit, its light passes through the light pipe 26 to
illuminate the window 28.
The electroluminescent panel 36 is conventionally formed as a
sandwich of areas of electroluminescent phosphor material 46 and
electrical conductors 48 and 50 sandwiched between supporting
transparent layers 52 and 54 of mylar material. The phosphor
material 46 underlies the graphics region 34 but not the window
28.
In order to shield the graphics region 34 from the lamp 38, an
opaque coating 56 is provided on a portion of the lower mylar layer
52. It is preferable that only a portion of the layer 52 is
provided with the opaque coating 56. This is because if the entire
layer 52 was formed of an opaque material, colorant in the mylar
can adversely affect the dielectric properties of the
electroluminescent material, which affects the life of the lamp.
Further, if the opaque material were coated over the entire surface
of the layer 52, or if the layer 52 were to be opaque, this would
interfere with proper registration of the layers of the
electroluminescent panel 36 during its manufacture.
As a further aid in shielding the graphics region 34 from the lamp
38, flaps 58 and 60 formed from the coated layer 52 extend into the
opening 42. The flaps 58 and 60 preferably interfere with the wall
24, as may be seen from FIGS. 1 and 2, but since the flaps 58 and
60 flex at the edge of the opening 42, this does not create a
problem.
Accordingly, there has been disclosed an improved illuminated
switch assembly. It is understood that the above-described
embodiment is merely illustrative of the application of the
principles of this invention. Numerous other embodiments may be
devised by those skilled in the art without departing from the
spirit and scope of this invention, as defined by the appended
claims.
* * * * *